A chaotic scene broke out while Michele Bachmann met with volunteers at her campaign office this afternoon, where police arrested 10 people.

Another eight people were later arrested outside the offices of Newt Gingrich and Rick Santorum.

Unlike orderly arrests at Occupy the Caucus protests earlier this week, police were waiting for demonstrators outside of Bachmann’s office and instructed them to stay on public ground. Two officers attempted to block at least 90 people from reaching the campaign office doors at a strip mall in Urbandale.

But chanting demonstrators marched past and gathered at the office doors, where Bachmann had arrived to meet with volunteers. More officers arrived as the protest progressed.

David Goodner, a member of Occupy Des Moines, urged demonstrators to stay tightly grouped to gain safety in numbers.

Among those arrested outside of Bachmann’s office were David Goodner, 30, of Occupy Des Moines and two minors, Heaven Chamberlin, 16, and Frankie Hughes, 14. Hughes had been arrested at a protest earlier this week. No one appeared to resist arrest.

The crowd, many shooting video and taking pictures on cell phones, booed and chanted, “Shame on you,” as police cuffed the teenagers and placed them in the back seats of police cars.

Bachmann later called the protesters “Obama’s re-election advance team,” who came to her office because she is the biggest threat to defeat President Barack Obama.

No one had planned to be arrested when the demonstrations were organized this morning, said Tony Tyler, 30, a member of Occupy Des Moines.

“We went up to the doors to express our concerns, and instead they’d rather have us arrested,” he said.

At around 2 p.m., about 45 minutes after arriving, the remaining protesters loaded onto three buses and several vehicles lef the campaign offices, at the 2700 block of 86th Street, in Urbandale to head to Rick Perry’s campaign offices. The later traveled to the offices of Gingrich and Santorum.

Protesters finished the day at the closed offices of Obama, organizers said this morning.

About two dozen people arrived today from Texas, Michigan, Minnesota, Kansas and Illinois, organizers said.

Today is the fourth day of protests in advance of Tuesday’s Iowa caucuses. Since Tuesday, people have descended on Des Moines from 25 states, Washington, D.C., and the countries of Canada, Mexico, Japan and the United Kingdom, organizers said.

Des Moines police made 27 arrests Wednesday and Thursday at four protest locations.

Protesters started the day marching from the East Village neighborhood in downtown Des Moines, up to the steps of the state Capitol and to an encampment of Occupy Des Moines protesters at Stewart Square, a public park at East 14th Street and Grand Avenue.